JPH0343420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a lattice beam used as a frame in prefabricated houses and the like.

[Background technology]

As shown in Fig. 1, conventional lattice beams include a plurality of vertical members 3 made of C-shaped steel with a U-shaped cross section, installed between an upper chord member 1 and a lower chord member 2, and lattice bars 10 (13mm It is often used that is formed by attaching a diameter of about 100 mm between the upper chord member 1 and the lower chord member 2. However, in this case where the structural strength of the lattice beam is provided by the lattice reinforcements 10, the reinforcing effect of the lattice reinforcements 10 cannot be obtained to a high degree, so as shown in FIG. W
It was necessary to adopt a letter-shaped arrangement and also to attach lattice strips 10 on both sides of the upper and lower chord members 1 and 2 as shown in FIG. Therefore, in this one, the lattice muscle 10
Because of the W-shaped arrangement, the area surrounded by the lattice strips 10 becomes small, making it impossible for people to pass through during electrical work, etc., and sometimes the lattice strips 10 have to be cut. Moreover, since the lattice muscle 10 is attached to both sides of the upper and lower chord members 1 and 2, the lattice muscle 1
There was also the problem that the weight of the lattice beam itself increased due to the increased weight of the lattice beam. In addition, upper and lower chord members 1 and 2
When attaching the lattice reinforcement 10 by welding 11, the welding work must be carried out while supporting the lattice reinforcement 10 by hand, which makes the work difficult. Piece 12,1
There was also the problem that automatic welding such as spot welding could not be performed because it was necessary to perform welding on the inner surface of the weld.

Therefore, instead of the lattice muscle 10, a C-shaped cross section is used.
There is also a lattice beam that uses diagonal members 4' made of shaped steel. Conventionally, the third type of lattice beam was
The configuration shown in the figure was used. In this case, one diagonal member 4' is installed between the vertical members 3 installed between the upper chord member 1 and the lower chord member 2. 4', it is necessary to make the width B of the diagonal member 4' wide. Therefore, when attaching the diagonal member 4' to the upper chord member 1 and the lower chord member 2, it is necessary to Since the section comes into contact with the upper part of the upper chord member 1 and the lower part of the lower chord member 2, it is necessary to cut both ends of the diagonal member 4 as shown in FIG. 4, which is a disadvantage in that the work is time-consuming. Also, for the one in Figure 3,
The intersection point of the neutral axis _L1 of the diagonal member 4' is not located on the neutral axis L2 of the upper and lower chord members 1 and ₂ , but is largely eccentric as shown in Figure 5, and a local bending moment is generated due to eccentric load. This was the cause of buckling. That is, in FIG. 5, the intersection O ₁ of the neutral axes L ₁ and L ₁ of the diagonals 4', 4' is the neutral axis of the diagonals 4', 4'.
The dimensions e ₁ and e 2 are eccentric from the intersections O ₂ and O ₃ between L ₁ and L ₁ and _the neutral axis L ₂ of the lower chord 2, and the neutral axis L ₁ and the neutral axis
If the angle formed with L ₂ is θ, P ₁ is attached to one diagonal member 4'.
When a force of P ₂ is applied to the other diagonal member 4', moments of P ₁ e ₁ Sin θ and P ₂ e ₂ Sin θ are generated in opposite directions around point O, and buckling occurs. It is. Here, the neutral axis is also referred to as the center axis, and refers to an axis in which the compressive stress and tensile stress generated by bending force are each zero.

[Purpose of the invention]

The present invention has been made in view of the above points, and provides a lattice beam that has excellent strength, eliminates the need to cut the ends of diagonal members, facilitates welding work, and is lightweight. The purpose is to

[Disclosure of the invention]

In the lattice beam according to the present invention, a plurality of vertical members 3 are installed between an upper chord member 1 having a U-shaped cross section and an open bottom surface and a lower chord member 2 having a U-shaped cross section and an open upper surface. A pair of diagonal members 4 are arranged in a V-shape, and their upper ends are welded and fixed in the upper chord member 1 and their lower ends are welded and fixed in the lower chord member 2, respectively, and the intersection of the extension lines of the neutral axes of both diagonal members 4 is connected to the upper chord member 1. is located on the neutral axis of the upper chord member 1 and the lower chord member 2, and the opening width of the upper chord member 1 and the lower chord member 2 and the outer width dimension of the diagonal member are set to be approximately the same. The present invention, which has achieved the above object, will be described in detail below with reference to Examples.

The upper chord member 1 and the lower chord member 2 each have a C-shaped cross section.
It is made of shaped steel, and a plurality of vertical members 3 made of metal plates are attached at predetermined intervals between the upper chord member 1 and the lower chord member 2, and reinforcing plates 5 are attached between both ends of the upper chord member 1 and the lower chord member 2, respectively. There is. Between 3 vertical members and 3 vertical members
A pair of diagonal members 4 made of C-shaped steel each having side pieces 4b and 4b on both sides of a center piece 4a and a U-shaped cross section are disposed between the reinforcing plate 5 and the center piece 4a. It is installed between the upper and lower chord members 1 and 2. Therefore, the pitch between the vertical members 3 is supported by the two diagonal members 4, 4 arranged in a V-shape, so the width B' of the side pieces 4b of the diagonal members 4 is narrow as shown in Fig. 7. Therefore, when the end of the diagonal member 4 is inserted into the upper chord member 1 or the lower chord member 2, the diagonal member 4 as shown in FIG.
Even if the end of the side piece 4b of the diagonal member 4 is cut at a right angle, it will not hit the upper part of the upper chord member 1 or the lower part of the lower chord member 2, and the end of the side piece 4b of the diagonal member 4 can be cut at a right angle, as in the conventional example shown in FIG. There is no need to cut diagonally, and the work can be streamlined. Further, as shown in FIG. 9, the outer width dimension A of the center piece 4a of the diagonal member 4 is set to be the same as the opening width dimension A' between the side pieces 12, 12 of the upper chord member 1 and the lower chord member 2. When assembling the lattice beam, if the diagonal members 4 are press-fitted into the upper chord members 1 and the lower chord members 2, the diagonal members 4 will be held between the upper chord members 1 and the lower chord members 2, and the diagonal members 4 will be held between the upper chord members 1 and the lower chord members 2. The diagonal member 4 can be welded and fixed without having to support it by hand. Further, each diagonal member 4 is installed between the upper and lower chord members 1 and 2 so that the opening faces upward, and the neutral axis L ₁ of the adjacent diagonal members 4, 4 is fixed as shown in FIG. , L ₁ is located on the neutral axis L ₂ of the upper chord member 1 and the lower chord member 2.
Therefore, in this case, since e ₁ and e ₂ in Fig. 5 are zero, no moment is generated to cause buckling, and local buckling can be prevented by avoiding eccentric loads on the upper and lower chord members 1 and 2. This can be suppressed. Further, a reinforcing plate 5 is attached to the vertical member 3 located at the end, and due to the presence of this reinforcing plate 5, the diagonal member 4 located at the end has a different angle of inclination than other diagonal members 4. Due to the difference in the angle of inclination, concentrated stress is applied to the diagonal member 4 at the end. Therefore, as shown in Fig. 10, diagonal members 4
An insertion notch 6 is provided at the upper end of the center piece 4a, and this insertion notch 6 is inserted into the reinforcing plate 5.
By inserting the insertion notch 6 into the reinforcing plate 5 in this way, the width of the reinforcing plate 5 attached between the upper and lower chord members 1 and 2 is absorbed by the insertion notch 6, so that the reinforcing plate 5 does not get in the way. The diagonal member 4 at this end can be installed at the same inclination angle as the diagonal member 4 between the other vertical members 3 without causing the diagonal member 4 to become fixed, and the inclination angle of the diagonal member 4 can be made constant, thereby preventing the occurrence of concentrated stress. This allows stress to be transmitted more smoothly to the columns than to the lattice beams.

In the above embodiment, a continuous module lattice beam is shown in which a plurality of diagonal members 4 are provided as one unit, but as shown in FIG. It may also be formed into a beam.

The lattice beam A formed as described above is used as a frame of a building as shown in FIG.
In Figure 12, 15 is the main house, 16 is the wall side purlin, 17 is the bundle, 18 is the keraba support, 19 is the gable side cantilever, 20
It is a cantilever beam. When attaching the wall horizontal bundles 21 to the lattice beam A, the wall horizontal bundles 21 can be fixed directly to the vertical members 3 with bolts and nuts as shown in Figure 13a, or they can be fixed directly to the vertical members 3 with bolts and nuts as shown in Figures 13b, c, and d. This can be done by fixing the wall horizontal bundles 21 to the vertical members 3 via the wall horizontal bundle receivers 22 with bolts and nuts. Further, the cantilever beam 23 can be attached to the lattice beam A by fixing it to the vertical member 3 as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, problems such as those when using lattice beams, such as the problem that a person cannot pass through the lattice beam by arranging the lattice beam in a W-shape, and the problem that lattice beams are used as upper and lower chord members, can be solved. Since the diagonals have to be installed on both sides of the beam, which increases the weight, the diagonals are arranged in a V-shape and are installed between the upper and lower chord members, so two diagonals can be used to create a lattice beam. Since the strength of one module is developed, thin diagonals can be used, and manufacturing costs are reduced without the need to cut the diagonals as in the conventional example shown in Figure 4. It is possible. Furthermore, since the intersection of the extension lines of the neutral axes of the diagonal members is located on the neutral axes of the upper and lower chord members, it is possible to suppress the generation of a moment that would cause buckling in the lattice beam. It is something. In addition, since the opening width of the upper and lower chord members and the outer width of the diagonal member are set to be approximately the same, when assembling the lattice beam, by fitting the diagonal member into the upper and lower chord members, the diagonal member can be held between the upper and lower chord members, and the diagonal members can be easily welded and fixed without the need to support the diagonal members by hand.

[Brief explanation of drawings]

Figure 1 is a front view of a conventional example, Figure 2 is an enlarged side sectional view of the same as above, Figure 3 is a front view of another conventional example, and Figure 4 is a front view of a conventional example.
5 is an enlarged view showing the same problem as above, FIG. 6 is a front view of an embodiment of the present invention, FIGS. 7 and 8,
Figure 9 is an enlarged view of the same as above, Figures 10 a and b are a plan view and perspective view of a part of the same as above, Figure 11 is a perspective view of another embodiment of the same as above, Figure 12 is the state in which the lattice beam is used. FIGS. 13a to 13d are perspective views showing the same in use, and FIG. 14 is a reduced perspective view in the same use. 1 is the upper chord member, 2 is the lower chord member, 3 is the longitudinal member, and 4 is the diagonal member.

Claims (1)

[Claims] 1. A plurality of vertical members are installed between a top chord member with a U-shaped cross section whose bottom surface is open and a lower chord member with a U-shaped cross section whose top surface is open, and a pair of diagonal members with a U-shaped cross section are arranged in a V-shape. Its upper end is welded and fixed within the upper chord member, and its lower end is welded and fixed within the lower chord member, and the intersection of the extension lines of the neutral axes of both diagonal members is located on the neutral axis of the upper and lower chord members, and the upper and lower chord members are fixed by welding. A lattice beam in which the opening width and the outer width of the diagonal members are set to approximately the same dimension.